This　paper　presents　state-of-the-art　review　on　the　fundamental　and　frontier　research　of　flow　boiling　heat　transfer,　mechanisms　and　prediction　methods　including　models　and　correlations　for　heat　transfer　in　micro　scale　channels.　First,　fundamental　issues　of　current　research　on　flow　boiling　in　microscale　channels　are　addressed.　These　mainly　include　the　criteria　for　macroscale　and　microscale　channels.　Then,　studies　on　flow　boiling　heat　transfer　behaviours　and　mechanisms　in　microscale　channels　are　presented.　Next,　the　available　correlations　and　models　of　flow　boiling　heat　transfer　in　microscale　channels　are　reviewed　and　analysed.　Comparisons　of　12　correlations　with　a　database　covering　a　wide　range　of　test　parameters　and　8　fluids　are　presented.　It　shows　that　all　correlations　poorly　agree　to　the　database.　No　generalized　model　or　correlation　is　able　to　predict　all　flow　boiling　heat　transfer　data.　Furthermore,　comparisons　of　the　mechanistic　flow　boiling　heat　transfer　models　based　on　flow　patterns　including　the　Thome　et　al.　three-zone　heat　transfer　model　for　evaporation　in　microchannel　and　the　flow　pattern　based　model　combining　the　Thome　et　al.　three　zone　heat　transfer　models　with　the　Cioncolini-Thome　annular　flow　model　for　both　macro-and　microchannel　to　the　database　are　presented.　It　shows　that　the　flow　pattern　based　model　combining　the　three　zone　model　with　the　annular　flow　model　gives　better　prediction　than　the　three　zone　heat　transfer　model　alone.　The　flow　pattern　based　heat　transfer　model　favourably　agrees　with　the　experimental　database　collected　from　the　literature.　According　to　the　comparison　and　analysis,　suggestions　have　been　given　for　improving　the　prediction　methods　in　the　future.　Next,　flow　patterned　based　phenomenological　models　and　their　applications　to　microscale　channels　are　presented.　Finally,　as　an　important　topic,　unstable　and　transient　flow　boiling　phenomena　in　microscale　channels　are　briefed　and　recommendations　for　future　research　are　given.　According　to　this　comprehensive　review　and　analysis　of　the　current　research　on　the　fundamental　issues　of　flow　boiling,　mechanisms　and　prediction　methods　in　microscale　channels,　the　future　research　needs　have　been　identified　and　recommended.　In　general,　systematic　and　accurate　experimental　data　of　flow　boiling　heat　transfer　in　microscale　channels　are　still　needed　although　a　large　amount　of　work　has　been　done　over　the　past　decades.　The　channel　size　effect　on　the　flow　boiling　behaviours　should　be　systematically　investigated.　Heat　transfer　mechanisms　in　microscale　channels　should　be　further　understood　and　related　to　the　corresponding　flow　patterns.　Furthermore,　effort　should　be　made　to　develop　and　improve　generalized　mechanistic　prediction　methods　and　theoretical　models　for　flow　boiling　heat　transfer　in　microscale　channels　according　to　the　physical　phenomena/mechanisms　and　the　corresponding　flow　structures.　The　effects　of　the　channel　size　and　a　wide　range　of　test　conditions　and　fluid　types　should　be　considered　in　develop　new　methods.　Furthermore,　systematic　experimental,　analytical　and　modeling　studies　on　unstable　and　transient　flow　boiling　heat　transfer　in　microscale　channels　should　be　conducted　to　understand　the　physical　mechanisms　and　theoretical　models.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.